Security Fixes

• System packages have been updated to their latest security versions.
• Updates Slanger to latest version (0.6.1) to address RCE vulnerability.

Bug fixes

• Fixes an issue where builds were not correctly using Xenial workers even if the correct configuration was provided.
• GitHub webhook creation will now correctly respect the 'disable ssl verification' option found in settings.

Known Issues

• Travis CI Enterprise will still write to the old log after log rotation
• Migrations and database creation are not run by default on startup when in HA mode. Have to run te-db-migrate and then te-db-migrate-logs manually on the platform host.
• In HA mode canceling an individual job of a build matrix can return a 502
• no_proxy not honored by travis-tasks (eg GitHub status updates, Slack Updates, etc)
• When using a GitHub Enterprise instance in Private Mode, user/repository avatar images will not show up in emails nor will the build status image in repository README files.
• When using a self-signed cert some images may not show in some email clients
• HTTPS clones fail when GitHub Enterprise instance is using a self-signed cert